I love this one...

Here is a link that might be useful: Quarter Sheet Pan

... and I love these.

Here is a link that might be useful: Goldtouch

Go to your local bakery and ask them what they use. I use aluminum sheets from the restaurant supply.

Vollrath (used to be Wearever), #5314. Heavy 13 gauge. I haven't found anything better, and I have had several. And, since it's rimmed, it does double- and triple-duty as a pan to put under pie to catch juice drippings, a sheet cake pan, a pan to roast vegetables, and several other things. Though I have been wanting to try the Goldtouch that Shear Stupidity linked above. I have a Goldtouch loaf pan, and it's the best loaf pan I've ever used. But, since I already own two of the Vollrath sheets, I have no need at this time to buy another.

Here is a link that might be useful: Vollrath 5314 Sheet

I second the suggestion for goldtouch. i have most of the goldtouch bakeware line and absolutely love it all!

I know this is an older thread, but the best thing to use for cookies is a Silpat sheet on a perforated baking sheet.

Here is a link that might be useful: Silpat.com